Wyniki wyszukiwania - BazTech

1

New 14C data of megafaunal remains from Lithuania : implications for the palaeoenvironmental interpretation of the Middle Weichselian

Satkūnas Jonas, Girininkas Algirdas, Rimkus Tomas, Daugnora Linas, Grigienė Alma, Stančikaitė Miglė, Slah Gvidas, Skuratovič Žana, Uogintas Domas, Žulkus Vladas

Geological Quarterly

|

2023

|

Vol. 67, No. 1

art. no. 3

EN

Palaeobiological data, supplemented by new 14C dates in conjunction with palaeobotanical and lithological information, have allowed reconstruction of Middle Weichselian (MIS 3) environmental fluctuations in the southern Eastern Baltic region. Palaeoenvironmental reconstructions implying non-glacial conditions during the Middle Weichselian (MIS 3) are supported by the spatial and temporal context of recently discovered remains of Mammuthus primigenius Blumenbach and Rangifer tarandus Linnaeus, 1758. Recording both cold and warm climatic reversals of MIS 3, representatives of the megafauna thrived in an environment characterized by a heterogeneity of vegetation and climate. 14C dating shows that the majority of the megafaunal remains analysed represent the 38–45 cal kyr BP time-interval, which correlates with the Nemunas 2c cold interval (cryomer), and the 31–34 cal kyr BP or Mickñnai 3 thermomer. From pollen data, the palaeovegetation pattern varied from tree-less tundra to birch-predominating forest with an admixture of temporal tree species providing additional information about the diet and habitat preferences of these herbivores in the context of the MIS 3 climatic events.

2

Investigation of CO2 Capture Property of CaO Sorbent in Various Molten Chloride Media with Different Operation Temperature

Kim Sung-Wook, Jeon Min Ku, Lee Kirak

Archives of Metallurgy and Materials

|

2020

|

Vol. 65, iss. 3

1051--1055

EN

CaO sorbent dissolved in chloride molten salts was investigated to identify its CO2 capture property. Various molten salt systems with different melting points (CaCl2 , LiCl, LiCl-CaCl2 , and LiCl-KCl) were used to control the operation temperature from 450 to 850ºC in order to determine the effect of the operation temperature on the chemical reaction between CaO and CO2 . The CaO sorbent showed the best performance at 550ºC in the LiCl-CaCl2 molten salt (conversion ratio of 85.25%). This temperature is lower than typical operation temperature of the solid-state CaO sorbent (~700ºC).

3

Radiocarbon 14C method as useful tool for flue gas monitoring application: review

Stachów M.

Budownictwo i Inżynieria Środowiska

|

2016

|

Vol. 7, no. 4

247--251

EN

Cosmic-ray research which started just after the second world war in 1947, encouraged widespread use of radioactive particles in many areas of science and technology, starting from astronomy, chemistry, archaeology, biology, botany, medicine and lately ending with environmental studies. Method based on measurements of the radioactive elements remains in various samples (solid, liquid and gaseous) can be very useful tool for ecological and environmental analytical measurements. The 14C liquid scintillating counting method was used for simplified determination of the biomass content in flue gas from combustion processes or in the finished bio-product. Review of the latest results and progress in this research area shows the growth of interest from industrial sector in normalised method for biomass content determination.

4

Holocene sediments of the Ustka Cliff (Northern Poland) in view of radiometric dating

Wróblewski R., Fedorowicz S., Kamieńska K.

Geochronometria

|

2013

|

Vol. 40, no. 3

187--194

EN

The cliff in Ustka is an active one. The area is one of the most eroded sea shores of the Polish coast. The Ustka Cliff mainly consists of Holocene sandy deposits, but its basis is built of gla-cial till and clay. Field search allowed to recognize the structure and sedimentary conditions of Holo-cene deposits exposed in the cliff. A comparison of dating results obtained for fossil soils and peat as well as aeolian deposits, using 14C and TL methods, respectively, with available literature records is presented. The evaluation of results obtained allowed to define three main dune-forming phases for the first time for this part of the Polish coast. During the research studies new data on the processes and environmental conditions was gained and the development of structure of the area during the last 10 thousand years was reconstructed. The analysis of available data from other sections of the south-ern Baltic coast shows that results obtained are age similar to those determined for the Łeba Spit. The research is part of a project concerning the geomorphology of the Ustka Bay.

5

Effect of liquid scintillating cocktail volume on 3H and 14C measurement parameters using a Quantulus spectrometer

Komosa A., Ślepecka K.

Nukleonika

|

2010

|

Vol. 55, No. 2

155-161

EN

Results of study on the influence of cocktail volume on such measuring parameters as counting efficiency, standard quench parameter (SQP) and figure of merit (FOM) are described. Nine commercial cocktails were tested using a Quantulus spectrometer. Two kinds of vials (low-diffusion teflon-coated polyethylene (LD-PE) and high-performance glass (HP-G)) and two standard solutions (14C and 3H) were used. Measurements were performed at seven quench levels ensured by carbon tetrachloride addition to the scintillation vials. Various quench sensitivity of the studied cocktails was found. Cocktails based on simple benzene-derived solvents revealed the best quench resistance. In general, increasing cocktail volume caused an increase in the counting efficiency. However, the background increased as well, what resulted in FOM diminishing. Studied cocktails revealed also various responses to volume changes.

6

Differentiation between fossil and biofuels by liquid scintillation beta spectrometry - direct method

Edler R., Kaihola L.

Nukleonika

|

2010

|

Vol. 55, No. 1

127-131

EN

Liquid scintillation spectrometry of 14C in gasoline/ethanol and diesel oil was carried out using QuantulusŽ and straight mixtures of fuel and an organic scintillation cocktail. A linear correlation was found between the concentration of carbon that originates from the bioethanol (biocarbon) and the fuel mixture’s 14C activity in the range 0–100% (m/m) bioethanol content. Because of these good linear correlations, quantitative determination of a fuel’s biocarbon content can be made by 14C analysis. The direct method is also applicable to analysis of the bio-based materials dissolvable in solvents, which can be mixed with scintillation cocktails.

7

A multi-layer box model of carbon dynamics in soil

Kuc T.

Nukleonika

|

2005

|

Vol. 50, nr 2

49-55

EN

Abstract A multi-layer box model (MLB) for quantification of carbon fluxes between soil and atmosphere has been developed. In the model, soil carbon reservoir is represented by two boxes: fast decomposition box (FDB) and slow decomposition box (SDB), characterised by substantially different turnover time (TT) of carbon compounds. Each box has an internal structure (sub-compartments) accounting for carbon deposited in consecutive time intervals. The rate of decomposition of carbon compounds in each sub-compartment is proportional to the carbon content. With the aid of the MLB model and the 14C signature of carbon dioxide, the fluxes entering and leaving the boxes, turnover time of carbon in each box, and the ratio of mass of carbon in the slow and fast box (Ms/Mf) were calculated. The MBL model yields the turnover time of carbon in the FDB (TTf) ca. 14 for typical investigated soils of temperate climate ecosystems. The calculated contribution of the CO2 flux originating from the slow box (Fs) to the total CO2 flux into the atmosphere ranges from 12% to 22%. These values are in agreement with experimental observations at different locations. Assuming that the input flux of carbon (Fin) to the soil system is doubled within the period of 100 years, the soil buffering capacity for excess carbon predicted by the MLB model for typical soil parameters may vary in the range between 26% and 52%. The highest values are obtained for soils characterised by long TTf, and well developed old carbon pool.